Discontinuous reception mode with two-stage wake-up

ABSTRACT

Systems and method of embodiments herein operate to conserve battery power of user equipment (UE). Embodiments determine whether waking up a UE receiver would be beneficial and based on the determination, the UE either wakes up the receiver or returns to sleep. Embodiments determine whether to wake up the receiver by performing pre-wake up (PWU) operation which either wakes up the receiver in a low power mode or wakes up the UE&#39;s wake up receiver. It may be determined whether a wake up (WU) signal is received during a PWU stage. If a WU signal is received during the PWU stage the UE may perform a full wake up of the receiver. If a WU signal is not received the UE may return to idle mode. In embodiments, WU (Wake Up) DRX cycles are supplemented with a Full DRX (Discontinuous Reception) cycle.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application is a continuation of commonly assigned, U.S.patent application Ser. No. 15/459,758 entitled “DISCONTINUOUS RECEPTIONMODE WITH TWO-STAGE WAKE-UP,” filed Mar. 15, 2017, which itself claimsthe benefit of priority to U.S. provisional patent application No.62/402,816, entitled, “DISCONTINUOUS RECEPTION MODE WITH TWO-STAGEWAKE-UP,” filed on Sep. 30, 2016, and a continuation-in-part ofco-pending, commonly assigned, U.S. patent application Ser. No.14/815,520 entitled “LOW POWER DISCONTINUOUS RECEPTION WITH A SECONDRECEIVER,” filed Jul. 31, 2015, which itself claims the benefit ofpriority to U.S. provisional patent application Nos. 62/077,058 entitled“LOW POWER DISCONTINUOUS RECEPTION WITH A SECOND RECEIVER,” filed Nov.7, 2014 and 62/075,088 entitled “LOW POWER DISCONTINUOUS RECEPTION WITHA SECOND RECEIVER,” filed Nov. 4, 2014, the disclosure of each of whichis hereby incorporated by reference herein in its entirety as if fullyset forth below and for all applicable purposes.

TECHNICAL FIELD

Aspects of the present disclosure relate generally to wirelesscommunication systems, and more particularly, to radio resourcemanagement. Certain embodiments of the technology discussed below canenable and provide features and techniques for efficient andpower-conserving communication systems.

INTRODUCTION

As user equipment (UE) get smaller and the services offered thereongrow, the real estate of hardware within the UE becomes more and morescarce and expensive. That being said, user's also desire that their UEhave increased battery life. While the obvious solution to increasingbattery life is to include a larger battery that stores more energy,such a solution is limited by the aforementioned real estate issues. Assuch, rather than increasing battery life by via battery size andstorage capacity, the industry has begun attempting to increase batterylife by reducing the UE's power consumption. Using such techniques, abattery of the same storage capacity is capable of lasting longerbecause less of the stored energy is being used.

In Long Term Evolution (LTE), the UE needs to monitor Physical DownlinkControl Channel (PDCCH) continuously (during a specified active durationevery DRX cycle) and this drains UE battery power heavily. Morespecifically, LTE addressed this issue of battery life in part by usinga two-mode Discontinuous Reception (DRX) mode. While in Radio ResourceControl (RRC) Idle mode of DRX operation (known as DRX in RRC Idle orI-DRX), the UE operates to monitor PDCCH discontinuously for P-RNTI(e.g., the UE monitors P-RNTI in PDCCH, only at predetermined periods,such as every 60 ms or 100 ms) to reduce UE power consumption. Incontrast to I-DRX mode which is mainly designed for page monitoring andoptimized for reception only operation, Connected DRX (C-DRX) mode isdesigned for a RRC connection between the UE and eNodeB where the UE isexpected to receive and transmit. In C-DRX mode operation, even if thetraffic is downlink mobile termination (MT) data, the UE needs totransmit in the uplink to facilitate control signaling of data, such asfeedback acknowledgement for the decoded data. Accordingly, the C-DRXmode provides an “ON duration” wherein the UE is operable to receive andtransmit and in which the UE monitors the PDCCH.

In LTE, the UE performs a Wake Up (WU) process to transition into C-DRXmode according to a pre-determined schedule. Because during sleep timethe UE's state information (such as timing synchronization andinformation about the radio channel) may become outdated, the UE alsoneeds to perform operations such as AGC, TTL, FTL, channel estimation,etc., when it exits the sleep state. The WU process consumes asignificant amount of power. For example, LTE C-DRX requires that the UEbe fully ready for receiving and transmitting in the first subframe ofthe ON duration. To achieve this, the UE needs to wake up earlier, suchas to perform radio frequency (RF) warm up, baseband warm up (e.g., AGC,TTL, FTL, channel estimation which is feasible because LTE CRS is alwayson and no extra UE/eNodeB coordination is required) to get ready for theON duration. This requires significant warm-up or make-ready processingand drains power.

Performing the WU process according to schedule at a time when no datais actually being received is a waste of power consumption and shortensthe battery life unnecessarily. That is, if no data is to be scheduledfor transmission during the ON duration of the C-DRX mode, the energyfor waking up and warm up for potential data transfer is wasted. Addingfurther to the inefficiencies of the LTE C-DRX operation, channel stateinformation (CSI) from a previous subframe is used until new CSI isreported by the UE. If the DRX cycle is long, stale CSI may result inpoor scheduling decisions, MCS/precoder selection causing performanceloss, etc.

BRIEF SUMMARY OF SOME EMBODIMENTS

Embodiments provide improved efficiency through operation to determinewhether performing or completing a WU process is warranted (e.g., datais expected to be communicated from the eNB to the UE). If it isdetermined that a WU process is warranted, embodiments perform orcomplete the WU process. Additionally and/or alternatively, if it isdetermined that a WU process is not warranted, embodiment do not performor complete the WU process.

In one aspect of the disclosure, a method for providing power-conservingoperation of user equipment (UE) is provided. The method of embodimentsincludes performing a multiple stage wake up (WU) process configured toconditionally transition the UE from low power operation tocommunication ready operation, wherein a determination is made at afirst stage of the multiple stage WU process regarding transitioning oneor more receivers of the UE from the low power operation to thecommunication ready operation. The method of embodiments furtherincludes transitioning the one or more receivers from the low poweroperation to the communication ready operation at a second stage of themultiple stage WU process if it is determined that the one or morereceivers are to be transitioned to the communication ready operation atthe first stage of the WU process, and ending a cycle of the WU processwithout performing the second stage of the WU process to transition theone or more receivers from the low power operation to the communicationready operation if it is determined that the one or more receivers arenot to be transitioned to the communication ready operation at the firststage of the WU process.

In a further aspect of the disclosure, an apparatus for providingpower-conserving operation of user equipment (UE) is provided. Theapparatus of embodiments includes means for performing a multiple stagewake up (WU) process configured to conditionally transition the UE fromlow power operation to communication ready operation, wherein the meansfor performing the multiple stage WU process is configured to make adetermination at a first stage of the multiple stage WU processregarding transitioning one or more receivers of the UE from the lowpower operation to the communication ready operation. The apparatus ofembodiments further includes means for transitioning the one or morereceivers from the low power operation to the communication readyoperation at a second stage of the multiple stage WU process if it isdetermined that the one or more receivers are to be transitioned to thecommunication ready operation at the first stage of the WU process, andmeans for ending a cycle of the WU process without performing the secondstage of the WU process to transition the one or more receivers from thelow power operation to the communication ready operation if it isdetermined that the one or more receivers are not to be transitioned tothe communication ready operation at the first stage of the WU process.

In a still further aspect of the disclosure, a non-transitory computerreadable medium having program code recorded thereon for providingpower-conserving operation of user equipment (UE) is provided. Theprogram code includes program code for causing one or more computers toperform a multiple stage wake up (WU) process configured toconditionally transition the UE from low power operation tocommunication ready operation, wherein a determination is made at afirst stage of the multiple stage WU process regarding transitioning oneor more receivers of the UE from the low power operation to thecommunication ready operation. The program code of embodiments furtherincludes program code for causing the one or more computers totransition the one or more receivers from the low power operation to thecommunication ready operation at a second stage of the multiple stage WUprocess if it is determined that the one or more receivers are to betransitioned to the communication ready operation at the first stage ofthe WU process, and end a cycle of the WU process without performing thesecond stage of the WU process to transition the one or more receiversfrom the low power operation to the communication ready operation if itis determined that the one or more receivers are not to be transitionedto the communication ready operation at the first stage of the WUprocess.

In a yet further aspect of the disclosure, an apparatus for providingpower-conserving operation of user equipment (UE) is provided. Theapparatus includes at least one processor and a memory coupled to the atleast one processor. The at least one processor of embodiments isconfigured to perform a multiple stage wake up (WU) process configuredto conditionally transition the UE from low power operation tocommunication ready operation, wherein a determination is made at afirst stage of the multiple stage WU process regarding transitioning oneor more receivers of the UE from the low power operation to thecommunication ready operation. The at least one process or embodimentsis further configured to transition the one or more receivers from thelow power operation to the communication ready operation at a secondstage of the multiple stage WU process if it is determined that the oneor more receivers are to be transitioned to the communication readyoperation at the first stage of the WU process, and to end a cycle ofthe WU process without performing the second stage of the WU process totransition the one or more receivers from the low power operation to thecommunication ready operation if it is determined that the one or morereceivers are not to be transitioned to the communication readyoperation at the first stage of the WU process.

In one aspect of the disclosure, a method for providing power-conservingoperation of user equipment (UE) in a cellular communication network isprovided. The method of embodiments includes monitoring, by a UE, for acontrol signal during a pre-wake up (PWU) stage of a multiple stage wakeup (WU) process configured to either transition one or more receivers ofthe UE from low power operation to communication ready operation in a WUstage of the multiple stage WU process or end a cycle of the multiplestage WU process without performing the WU stage of the multiple stageWU process. The method of embodiments further includes transitioning theone or more receivers of the UE from low power operation tocommunication ready operation in the WU stage of the multiple stage WUprocess when it is determined that the one or more receivers are to betransitioned to the communication ready operation based on themonitoring for the control signal in the PWU stage or ending a currentcycle of the multiple stage WU process without performing the WU stagewhen it is determined that the one or more receivers are not to betransitioned to the communication ready operation based on themonitoring for the control signal in the PWU stage.

In a still further aspect of the disclosure, a non-transitorycomputer-readable medium having program code recorded thereon forproviding power-conserving operation of user equipment (UE) is provided.The program code includes program code for providing power-conservingoperation of user equipment (UE) in a cellular communication network.The program code includes program code for causing one or more computersto monitor for a control signal during a pre-wake up (PWU) stage of amultiple stage wake up (WU) process configured to either transition oneor more receivers of a UE from low power operation to communicationready operation in a WU stage of the multiple stage WU process or end acycle of the multiple stage WU process without performing the WU stageof the multiple stage WU process. The program code of embodimentsfurther includes program code for causing the one or more computers totransition the one or more receivers of the UE from low power operationto communication ready operation in the WU stage of the multiple stageWU process when it is determined that the one or more receivers are tobe transitioned to the communication ready operation based on themonitoring for the control signal in the PWU stage and to end a currentcycle of the multiple stage WU process without performing the WU stagewhen it is determined that the one or more receivers are not to betransitioned to the communication ready operation based on themonitoring for the control signal in the PWU stage.

In a yet further aspect of the disclosure, an apparatus for providingpower-conserving operation of user equipment (UE) is provided. Theapparatus includes at least one processor and a memory coupled to the atleast one processor. The at least one processor of embodiments isconfigured to monitor for a control signal during a pre-wake up (PWU)stage of a multiple stage wake up (WU) process configured to eithertransition one or more receivers of a UE from low power operation tocommunication ready operation in a WU stage of the multiple stage WUprocess or end a cycle of the multiple stage WU process withoutperforming the WU stage of the multiple stage WU process. The at leastone process or embodiments is further configured to transition the oneor more receivers of the UE from low power operation to communicationready operation in the WU stage of the multiple stage WU process when itis determined that the one or more receivers are to be transitioned tothe communication ready operation based on the monitoring for thecontrol signal in the PWU stage; and to end a current cycle of themultiple stage WU process without performing the WU stage when it isdetermined that the one or more receivers are not to be transitioned tothe communication ready operation based on the monitoring for thecontrol signal in the PWU stage.

Other aspects, features, and embodiments of the present invention willbecome apparent to those of ordinary skill in the art, upon reviewingthe following description of specific, exemplary embodiments of thepresent invention in conjunction with the accompanying figures. Whilefeatures of the present invention may be discussed relative to certainembodiments and figures below, all embodiments of the present inventioncan include one or more of the advantageous features discussed herein.In other words, while one or more embodiments may be discussed as havingcertain advantageous features, one or more of such features may also beused in accordance with the various embodiments of the inventiondiscussed herein. In similar fashion, while exemplary embodiments may bediscussed below as device, system, or method embodiments it should beunderstood that such exemplary embodiments can be implemented in variousdevices, systems, and methods.

BRIEF DESCRIPTION OF THE DRAWINGS

A further understanding of the nature and advantages of the presentdisclosure may be realized by reference to the following drawings. Inthe appended figures, similar components or features may have the samereference label. Further, various components of the same type may bedistinguished by following the reference label by a dash and a secondlabel that distinguishes among the similar components. If just the firstreference label is used in the specification, the description isapplicable to any one of the similar components having the same firstreference label irrespective of the second reference label.

FIG. 1 is a block diagram illustrating details of a wirelesscommunication system in which embodiments of the present invention maybe deployed.

FIG. 2 is a block diagram conceptually illustrating a design of a basestation/eNB and a UE configured according to one aspect of the presentdisclosure.

FIG. 3 illustrates operation of WU-DRX cycles according to an aspect ofthe present disclosure.

FIG. 4 is a flow diagram conceptually illustrating operation of a WU-DRXcycle according to an aspect of the present disclosure.

FIGS. 5 and 6 illustrate power profiles for a UE receiver operating inaccordance with WU-DRX processes according to some aspects of thepresent disclosure.

FIG. 7 illustrates power profiles for a UE receiver operating inaccordance with a LTE DRX process.

FIGS. 8 and 9 illustrate implementations of Full DRX cycles incombination with the WU-DRX cycles of WU-DRX processes according toaspects of the present disclosure.

DETAILED DESCRIPTION

The detailed description set forth below, in connection with theappended drawings, is intended as a description of various possibleconfigurations and is not intended to limit the scope of the disclosure.Rather, the detailed description includes specific details for thepurpose of providing a thorough understanding of the inventive subjectmatter. It will be apparent to those skilled in the art that thesespecific details are not required in every case and that, in someinstances, well-known structures and components are shown in blockdiagram form for clarity of presentation.

This disclosure relates generally to providing or participating incommunication as between two or more wireless devices in one or morewireless communications systems, also referred to as wirelesscommunications networks. In various embodiments, the techniques andapparatus may be used for wireless communication networks such as codedivision multiple access (CDMA) networks, time division multiple access(TDMA) networks, frequency division multiple access (FDMA) networks,orthogonal FDMA (OFDMA) networks, single-carrier FDMA (SC-FDMA)networks, LTE networks, GSM networks, as well as other communicationsnetworks. As described herein, the terms “networks” and “systems” may beused interchangeably according to the particular context.

A CDMA network, for example, may implement a radio technology such asuniversal terrestrial radio access (UTRA), cdma2000, and the like. UTRAincludes wideband-CDMA (W-CDMA) and low chip rate (LCR). CDMA2000 coversIS-2000, IS-95, and IS-856 standards.

A TDMA network may, for example implement a radio technology such asGlobal System for Mobile Communications (GSM). 3GPP defines standardsfor the GSM EDGE (enhanced data rates for GSM evolution) radio accessnetwork (RAN), also denoted as GERAN. GERAN is the radio component ofGSM/EDGE, together with the network that joins the base stations (forexample, the Ater and Abis interfaces) and the base station controllers(A interfaces, etc.). The radio access network represents a component ofa GSM network, through which phone calls and packet data are routed fromand to the public switched telephone network (PSTN) and Internet to andfrom subscriber handsets, also known as user terminals or userequipments (UEs). A mobile phone operator's network may comprise one ormore GERANs, which may be coupled with UTRANs in the case of a UMTS/GSMnetwork. An operator network may also include one or more LTE networks,and/or one or more other networks. The various different network typesmay use different radio access technologies (RATs) and radio accessnetworks (RANs).

An OFDMA network may, for example, implement a radio technology such asevolved UTRA (E-UTRA), IEEE 802.11, IEEE 802.16, IEEE 802.20, flash-OFDMand the like. UTRA, E-UTRA, and GSM are part of universal mobiletelecommunication system (UMTS). In particular, long term evolution(LTE) is a release of UMTS that uses E-UTRA. UTRA, E-UTRA, GSM, UMTS andLTE are described in documents provided from an organization named “3rdGeneration Partnership Project” (3GPP), and cdma2000 is described indocuments from an organization named “3rd Generation Partnership Project2” (3GPP2). These various radio technologies and standards are known orare being developed. For example, the 3rd Generation Partnership Project(3GPP) is a collaboration between groups of telecommunicationsassociations that aims to define a globally applicable third generation(3G) mobile phone specification. 3GPP long term evolution (LTE) is a3GPP project aimed at improving the universal mobile telecommunicationssystem (UMTS) mobile phone standard. The 3GPP may define specificationsfor the next generation of mobile networks, mobile systems, and mobiledevices.

For clarity, certain aspects of the apparatus and techniques may bedescribed below with reference to exemplary LTE implementations or in anLTE-centric way, and LTE terminology may be used as illustrativeexamples in portions of the description below; however, the descriptionis not intended to be limited to LTE applications. Indeed, the presentdisclosure is concerned with shared access to wireless spectrum betweennetworks using different radio access technologies or radio airinterfaces.

Moreover, it should be understood that, in operation, wirelesscommunication networks adapted according to the concepts herein mayoperate with any combination of licensed or unlicensed spectrumdepending on loading and availability. Accordingly, it will be apparentto one of skill in the art that the systems, apparatus and methodsdescribed herein may be applied to other communications systems andapplications than the particular examples provided.

FIG. 1 shows wireless network 100 for communication according to someembodiments. While discussion of the technology of this disclosure isprovided relative to an LTE-A network (shown in FIG. 1), this is forillustrative purposes. Principles of the technology disclosed can beused in other network deployments, including fifth generation (5G)networks. As appreciated by those skilled in the art, componentsappearing in FIG. 1 are likely to have related counterparts in othernetwork arrangements.

Turning back to FIG. 1 wireless network 100 includes a number of basestations, such as may comprise evolved node Bs (eNBs), referred toherein as eNBs 105 and other network entities. An eNB may be a stationthat communicates with the UEs and may also be referred to as a basestation, a node B, an access point, and the like. Each eNB 105 mayprovide communication coverage for a particular geographic area. In3GPP, the term “cell” can refer to this particular geographic coveragearea of an eNB and/or an eNB subsystem serving the coverage area,depending on the context in which the term is used. In implementationsof wireless network 100 herein, eNBs 105 may be associated with a sameoperator or different operators (e.g., wireless network 100 may comprisea plurality of operator wireless networks), and may provide wirelesscommunications using one or more of the same frequencies (e.g., one ormore frequency band in licensed spectrum, unlicensed spectrum, or acombination thereof) as a neighboring cell.

An eNB may provide communication coverage for a macro cell or a smallcell, such as a pico cell or a femto cell, and/or other types of cell. Amacro cell generally covers a relatively large geographic area (e.g.,several kilometers in radius) and may allow unrestricted access by UEswith service subscriptions with the network provider. A small cell, suchas a pico cell, would generally cover a relatively smaller geographicarea and may allow unrestricted access by UEs with service subscriptionswith the network provider. A small cell, such as a femto cell, wouldalso generally cover a relatively small geographic area (e.g., a home)and, in addition to unrestricted access, may also provide restrictedaccess by UEs having an association with the femto cell (e.g., UEs in aclosed subscriber group (CSG), UEs for users in the home, and the like).An eNB for a macro cell may be referred to as a macro eNB. An eNB for asmall cell may be referred to as a small cell eNB, a pico eNB, a femtoeNB or a home eNB. In the example shown in FIG. 1, eNBs 105 a, 105 b and105 c are macro eNBs for the macro cells 110 a, 110 b and 110 c,respectively. eNBs 105 x, 105 y, and 105 z are small cell eNBs, whichmay include pico or femto eNBs that provide service to small cells 110x, 110 y, and 110 z, respectively. An eNB may support one or multiple(e.g., two, three, four, and the like) cells.

Wireless network 100 may support synchronous or asynchronous operation.For synchronous operation, the eNBs may have similar frame timing, andtransmissions from different eNBs may be approximately aligned in time.For asynchronous operation, the eNBs may have different frame timing,and transmissions from different eNBs may not be aligned in time.

UEs 115 are dispersed throughout wireless network 100, and each UE maybe stationary or mobile. It should be appreciated that, although amobile apparatus is commonly referred to as user equipment (UE) instandards and specifications promulgated by the 3rd GenerationPartnership Project (3GPP), such apparatus may also be referred to bythose skilled in the art as a mobile station (MS), a subscriber station,a mobile unit, a subscriber unit, a wireless unit, a remote unit, amobile device, a wireless device, a wireless communications device, aremote device, a mobile subscriber station, an access terminal (AT), amobile terminal, a wireless terminal, a remote terminal, a handset, aterminal, a user agent, a mobile client, a client, or some othersuitable terminology. Within the present document, a “mobile” apparatusor UE need not necessarily have a capability to move, and may bestationary. Some non-limiting examples of a mobile apparatus, such asmay comprise embodiments of one or more of UEs 115, include a mobile, acellular (cell) phone, a smart phone, a session initiation protocol(SIP) phone, a laptop, a personal computer (PC), a notebook, a netbook,a smart book, a tablet, and a personal digital assistant (PDA). A mobileapparatus may additionally be an “Internet of things” (IoT) device suchas an automotive or other transportation vehicle, a satellite radio, aglobal positioning system (GPS) device, a logistics controller, a drone,a multi-copter, a quad-copier, a smart energy or security device, asolar panel or solar array, municipal lighting, water, or otherinfrastructure; industrial automation and enterprise devices; consumerand wearable devices, such as eyewear, a wearable camera, a smart watch,a health or fitness tracker, a mammal implantable device, gesturetracking device, medical device, a digital audio player (e.g., MP3player), a camera, a game console, etc.; and digital home or smart homedevices such as a home audio, video, and multimedia device, anappliance, a sensor, a vending machine, intelligent lighting, a homesecurity system, a smart meter, etc. A mobile apparatus, such as UEs115, may be able to communicate with macro eNBs, pico eNBs, femto eNBs,relays, and the like. In FIG. 1, a lightning bolt (e.g., communicationlinks 125) indicates wireless transmissions between a UE and a servingeNB, which is an eNB designated to serve the UE on the downlink and/oruplink, or desired transmission between eNBs. Although backhaulcommunication 134 is illustrated as wired backhaul communications thatmay occur between eNBs, it should be appreciated that backhaulcommunications may additionally or alternatively be provided by wirelesscommunications.

FIG. 2 shows a block diagram of a design of base station/eNB 105 and UE115, which may be one of the base stations/eNBs and one of the UEs inFIG. 1. For a restricted association scenario, the eNB 105 may be smallcell eNB 105 z in FIG. 1, and UE 115 may be UE 115 z, which in order toaccess small cell eNB 105 z, would be included in a list of accessibleUEs for small cell eNB 105 z. eNB 105 may also be a base station of someother type. eNB 105 may be equipped with antennas 234 a through 234 t,and UE 115 may be equipped with antennas 252 a through 252 r.

At eNB 105, transmit processor 220 may receive data from data source 212and control information from controller/processor 240. The controlinformation may be for the PBCH, PCFICH, PHICH, PDCCH, etc. The data maybe for the PDSCH, etc. Transmit processor 220 may process (e.g., encodeand symbol map) the data and control information to obtain data symbolsand control symbols, respectively. Transmit processor 220 may alsogenerate reference symbols, e.g., for the PSS, SSS, and cell-specificreference signal. Transmit (TX) multiple-input multiple-output (MIMO)processor 230 may perform spatial processing (e.g., precoding) on thedata symbols, the control symbols, and/or reference symbols, ifapplicable, and may provide output symbol streams to modulators (MODs)232 a through 232 t. Each modulator 232 may process a respective outputsymbol stream (e.g., for OFDM, etc.) to obtain an output sample stream.Each modulator 232 may additionally or alternatively process (e.g.,convert to analog, amplify, filter, and upconvert) the output samplestream to obtain a downlink signal. Downlink signals from modulators 232a through 232 t may be transmitted via antennas 234 a through 234 t,respectively.

At UE 115, antennas 252 a through 252 r may receive the downlink signalsfrom eNB 105 and may provide received signals to demodulators (DEMODs)254 a through 254 r, respectively. Each demodulator 254 may condition(e.g., filter, amplify, downconvert and digitize) a respective receivedsignal to obtain input samples. Each demodulator 254 may further processthe input samples (e.g., for OFDM, etc.) to obtain received symbols.MIMO detector 256 may obtain received symbols from all demodulators 254a through 254 r, perform MIMO detection on the received symbols ifapplicable, and provide detected symbols. Receive processor 258 mayprocess (e.g., demodulate, deinterleave, and decode) the detectedsymbols, provide decoded data for UE 115 to data sink 260, and providedecoded control information to controller/processor 280.

On the uplink, at UE 115, transmit processor 264 may receive and processdata (e.g., for the PUSCH) from data source 262 and control information(e.g., for the PUCCH) from controller/processor 280. Transmit processor264 may also generate reference symbols for a reference signal. Thesymbols from transmit processor 264 may be precoded by TX MIMO processor266 if applicable, further processed by modulators 254 a through 254 r(e.g., for SC-FDM, etc.), and transmitted to eNB 105. At eNB 105, theuplink signals from UE 115 may be received by antennas 234, processed bydemodulators 232, detected by MIMO detector 236 if applicable, andfurther processed by receive processor 238 to obtain decoded data andcontrol information sent by UE 115. Processor 238 may provide thedecoded data to data sink 239 and the decoded control information tocontroller/processor 240.

Controllers/processors 240 and 280 may direct the operation at eNB 105and UE 115, respectively. Controller/processor 240 and/or otherprocessors and modules at eNB 105 may perform or direct the execution ofvarious processes for the techniques described herein.Controllers/processor 280 and/or other processors and modules at UE 115may also perform or direct the execution illustrated in FIGS. 3-9,and/or other processes for the techniques described herein. Memories 242and 282 may store data and program codes for eNB 105 and UE 115,respectively. Scheduler 244 may schedule UEs for data transmission onthe downlink and/or uplink.

In order to conserve battery life, systems and methods of embodimentsherein operate to avoid performing or completing a Wake Up (WU) processprior to a connected mode of a discontinuous reception mode (e.g., C-DRXmode) upon determining that the WU process is not warranted (e.g., theWU process may not be useful for facilitating data communication) at aparticular point in time. In embodiments, before waking up a receiver,systems and methods operable in accordance with concepts herein mayfirst determine whether performing or completing a WU process iswarranted (e.g., data is expected to be communicated from the eNB to theUE). If it is determined that a WU process is warranted, a system mayperform or complete the WU process. Additionally and/or alternatively,if it is determined that a WU process is not warranted, the system maynot perform or complete the WU process.

In embodiments, systems and methods implement a WU process as amulti-stage process (referred to herein as WU-DRX), including a Pre-WakeUp (PWU) stage and a Wake Up (WU) stage. In operation according toembodiments, PWU stage operation is performed by a UE (e.g., any of UEs115 of FIGS. 1 and 2) first and, if the PWU stage operation determinesthat WU operation is warranted, WU stage operation is performed by theUE. Additionally and/or alternatively, if PWU stage operation determinesthat WU stage operation is not warranted, the UE may not perform the WUstage operation.

In operation of a WU-DRX process of embodiments, the PWU stage providesa PWU duration for control signal monitoring before an ON duration(e.g., an ON duration of C-DRX mode operation wherein a RRC connectionbetween the UE and eNodeB is provided in which the UE is configured toreceive and transmit). Example PWU durations are shown as PWU duration302 a of WU-DRX cycle 301 a and PWU duration 302 b of WU-DRX cycle 301 bof FIG. 3, wherein WU-DRX cycles 301 a and 301 b comprise subsequentWU-DRX cycle instances of a WU-DRX process. Whether the UE wakes up(e.g., WU stage operation is performed) for the ON duration isconditional on the detection of a control signal of embodiments. Forexample, WU-DRX cycle 301 a of FIG. 3 does not include an ON durationcorresponding to PWU duration 302 a. However, WU-DRX cycle 301 bincludes ON duration 303 b corresponding to PWU duration 302 b as aresult of detection of control signal 310.

Implementation of a PWU stage according to embodiments may utilize a lowpower receive mode for control signal monitoring. For example, a lowpower receive mode of a UE receiver otherwise used for datacommunication (e.g., a traditional or main UE receiver) may be utilizedfor control signal monitoring. Additionally or alternatively,implementation of embodiments of a PWU stage may utilize a wake-upreceiver (WUR) for control signal monitoring (e.g., a UE receiverconfigured to receive control signals of a PWU stage of a multi-stage WUprocess that is not otherwise used for data communication). For example,the WUR of embodiments receives and processes specialized signalingand/or waveforms, which reduce complexity and energy consumption. A WURmay, for example, perform non-coherent signal reception (e.g., signalreception that operates without the traditionally required informationsuch as channel estimation). A WUR of embodiments uses substantiallyless power as compared to the UE's traditional or main receiver, evenwith respect to some UE traditional or main receiver implementationsoperating in a low power receive mode. The low power receive mode andWUR embodiments of a PWU stage implementation facilitate a power savingPWU duration. Configurations of secondary receivers as may be utilizedas a WUR of embodiments herein are shown and described in co-pending andcommonly assigned U.S. patent application Ser. No. 14/815,520, entitled“LOW POWER DISCONTINUOUS RECEPTION WITH A SECOND RECEIVER,” thedisclosure of which is incorporated herein by reference.

One or more control signals (e.g., control signal 310 of FIG. 3) may beprovided to the UE during a PWU duration of a PWU stage of embodiments.For example, a full wake-up (WU) signal may be provided to the UE as acontrol signal in a PWU duration if data is to be expected during the ONduration. The full wake-up signal utilized according to embodiments maybe, for example, based on sequence detection (e.g., the UE may beassigned a particular modulation symbol sequence, and detection of whichmay mean the UE should perform “Full WU” during ON duration), based oncoding and modulation (e.g., whether the UE should perform “Full WU” maydepend on a bit in a payload that is coded and modulated and transmittedon assigned resources during the PWU period, and processedcorrespondingly and decoded successfully by the UE), based on positiondetection (e.g., the existence of energy in a particular tone orcombination of tones, such as using FSK, may signal whether the UE needsto perform “Full WU”), etc. In operation according to some embodiments,lack of detection of the signal may be used to indicate “Full WU”.Irrespective of the particular technique for full wake-up signalingused, the UE may proceed to the WU stage of a WU-DRX process for WUprocessing to initiate the ON duration upon detection of full WUsignaling in the PWU duration. However, the UE may return to sleep afterPWU duration if full WU signaling is not detected in the PWU duration.

A full WU signal utilized with respect to a PWU stage of embodiments maybe enhanced with various information useful with respect the WU process.For example, the full WU control signal may comprise informationregarding control channel assignment (e.g., subband and/or search spaceinfo) for the ON duration, data channel subband assignment and/orbandwidth information, kick off resource block allocation forcross-subframe scheduling, indication of upcoming reference signals usedfor baseband warm-up (e.g. AGC, TTL, FTL, channel estimation), etc.Additionally or alternatively, various information useful with respectthe WU process may be provided in the PWU duration separate from a fullWU signal (e.g., as another control signal provided during the PWUduration).

A triggering signal is another example of the control signals that maybe provided to the UE during a PWU duration of a PWU stage ofembodiments. For example, a trigger signal may provide triggering ofaperiodic CSI (e.g., CQI, PMI, RI) report procedure. For TDD withreciprocity, the UE may transmit a sounding reference signal (SRS)first. In operation according to embodiments, the eNB transmits CSI-RSahead of the ON duration for the UE to warm-up or make-ready thebaseband as well as report accurate CSI. In operation according toembodiments, resources utilized for the procedure may be semi-staticallyallocated.

It should be appreciated from the foregoing that, in addition to controlsignals provided in the downlink to the UE, a PWU duration of a PWUstage of embodiments supports uplink transmission of control signals.For example, a UE may operate in a PWU duration to transmit one or morecontrol signals such as SR, SRS, etc.

In operation of a WU-DRX process of embodiments, there may be a gapbetween a PWU duration of a PWU stage and an ON duration of a WU stage.For example, the transmitter (e.g., one or more transmitters of one ofeNBs 105 in communication with UE 115) may provide a gap of N subframesbetween PWU duration 302 b and corresponding ON duration 303 b WU-DRXcycle 301 b of FIG. 3. Such a gap between a PWU duration andcorresponding ON duration may be provided for various purposes. Forexample, the gap may be provided to enable offline (e.g.,non-time-critical) and/or low power processing of one or more controlsignals received in a PWU duration. Additionally or alternatively, a gapbetween a PWU duration and corresponding ON duration may be provided toallow time for baseband warm-up or make-ready before the ON duration.For example, performing the functions of a WU stage of a WU-DRX processof embodiments may take an amount of time that spans more than thelength of a subframe. Thus, a gap may be built into the transmittedframe after the grant (e.g., PDCCH) and before the transmission of data(e.g., PDSCH) to give the UE enough time to finish WU stage operation orsome portion thereof.

Various considerations may be used in determining the magnitude of thegap between a PWU duration and corresponding ON duration (e.g., thevalue of N in the above example). For example, N is selected to allowfor sufficient time for offline processing and preparing for datareception according to embodiments. As another consideration,embodiments may provide an option to allow for baseband warm-up ormake-ready for data reception towards end of N.

The gap between a PWU duration and corresponding ON duration can bezero, that is, effectively non-existent, according to embodimentsherein. Implementation of a zero or negligible gap between a PWUduration and corresponding ON duration may, for example, generally workfor a modem architecture where the modem is capable of finishingdecoding or otherwise processing the full WU signal within the PWUduration and can process data Rx/Tx immediately in the next subframe. Inoperation of the aforementioned example embodiment, the general conceptof WU signaling can still be applied, but because the subframesassociated with PWU duration and the start of the ON duration areconsecutive, the full WU signal could be interpreted as a stay-awakesignal. Regardless of the interpretation, the control signal provided inthe PWU stage may indicate whether the UE should remain active or notfor the ON duration, after the PWU duration.

The magnitude of the gap between a PWU duration and corresponding ONduration (e.g., the value of N, including instances where N=0) may bestatic, semi-static, or dynamic. For example, a semi-static setting forN may be provided in a RRC configuration setting. Additionally oralternatively, a control signal may dynamically indicate N (e.g., theWU-DRX cycle may be anchored on start of control duration).

The one or more control signals (e.g., full WU signals, trigger signals,etc.) of embodiments may be provided to the UE using various physicallayer implementations. For example, control signals (e.g., controlsignal 310 of FIG. 3) may be provided to a UE during a PWU duration of aPWU stage using a configuration wherein the control signals are smalland easily processed by the receiver in low power mode. Additionally oralternatively, control signals of embodiments may be multiplexed withcontrol and/or data channels of other UEs. For example, the full WUsignal utilized according to embodiments may be included in an indicatorchannel (ICH) or another channel similar to the paging channel thatsignals a grant will be scheduled in the current WU-DRX cycle. Thecontrol signals utilized according to embodiments may not only beprovided by unicast transmission, but may be provided by broadcast ormulti-cast transmission (e.g. common PDCCH). For example, the full WUsignal may be broadcast/multicast in group common PDCCH (e.g., abroadcast/multicast control channel), and the UEs may demultiplex theirsignal based on FDM/TDM/CDM rules associated with the channel. In thecase that the control signal is to be shared across multiple recipientsof the channel, if at least one recipient should be signaled to performa full wake-up, the shared control signal of embodiments may indicatethat all recipients should perform a full wake-up, although this maygive up some power saving opportunities as some users may perform a fullwake-up unnecessarily. Accordingly, unicast control signaling may beimplemented according to embodiments to maximize power saving. Forexample, when the system is lightly loaded, control resources may bedistributed to users such that unicasting of control signals herein(e.g., the full WU signal utilized according to embodiments may beincluded via Downlink Control information (DCI) in a unicast PDCCH) maybe used to the maximum extent possible and multicasting may be used forcontrol signaling as needed (e.g., only after control channel resourcesare depleted). In operation according to an exemplary unicast PDCCHembodiment, the payload or information useful for decoding the payload(e.g. CRC) may be scrambled with the UE-RNTI, and PDCCH for differentUEs may also be separated by FDM/TDM/CDM. In accordance with someembodiments where DCI is used to carry a full WU signal, PSDCH may beutilized to carry some information (e.g., various information usefulwith respect the WU process) and reduce the burden on DCI capacity.Embodiments operable to multiplex one or more control signals hereinwith control and/or data channels of other UEs provide implementationsfacilitating offline receiver processing conducive for low powerconsumption and may allow leveraging of hardware optimized for I-DRXmode operation.

A WUR configuration, as mentioned above, of embodiments is anotherexample of a physical layer implementation for providing the one or morecontrol signals (e.g., control signal 310 of FIG. 3) of a WU-DRX cycleto the UE. In accordance with embodiments, specialized signaling and/orwaveform (e.g., as may be adapted to reduce receiver complexity)utilized by a WUR may provide substantially lower power operation duringa PWU duration. For example, in an exemplary embodiment, non-coherentsignaling/reception is utilized by a WUR having reduced receivercomplexity for low power PWU stage operation. A WUR implementationhaving reduced receiver complexity may comprise an energy detectionbased receiver, such as may be incorporated into a RF transceiver chip(e.g., to provide for a baseband modem waking up only for traffic). If asignificant percentage of the WU-DX cycles are traffic-less, such a lowpower WUR may be beneficial.

Specialized signaling and/or waveform utilized as the one or morecontrol signals of a WU-DRX cycle (e.g., full WU signal, trigger signal,etc.) may be multiplexed with control and/or data channels of other UEsaccording to embodiments. Multiplexing on-off keying (OOK) signalswithin OFDM, for example, may readily be performed by both the eNBmodulator and a low power WUR implementation of embodiments. Detail withrespect to multiplexing/demultiplexing of a signal as may be used as aWU signal according to embodiments herein is shown and described in U.S.patent application Ser. No. 15/053,679 entitled “DOWNLINK MULTIPLEXINGAND MAC SIGNAL FOR A SYSTEM WITH DEVICES OPERATING WITH AND WITHOUT LOWPOWER COMPANION RECEIVERS,” filed Feb. 25, 2016, the disclosure of whichis incorporated herein by reference.

It should be appreciated that a WUR having reduced receiver complexitymay not be capable of decoding certain data, such as DCI in PDCCH.However, a UE of embodiments may desire to perform some maintenance typeof operations from time to time. For example, the UE may preform RadioLink Monitoring (RLM) (e.g., for a radio link failure condition),Channel State information processing and Feedback (CSF), Radio ResourceManagement (RRM) (e.g., neighbor cell measurement and/or search, servingcell measurement), and/or maintaining time and frequency synchronization(Sync) based on reference signal, which may dependent on the radiochannel and/or network. Such maintenance may be best handled by atraditional or main receiver operating at its normal power level asopposed to a WUR (e.g., some embodiments of a WUR may provide processingnot well suited for performing some types of maintenance activities).Accordingly, embodiments implementing a WUR may utilize another receiverof the UE to periodically perform one or more one or more maintenancetype operations.

UE power consumption associated with the WU-DRX process may be affectedby the particular physical channel used for WU-DRX control signaling,the PWU duration, the search space, the duration of the gap, and thepercentage of WU-DRX cycles in which no data is transmitted to the UE.As an example of UE power consumption being affected by the particularphysical channel used for control signaling, if using DCI in PDCCH, thefollowing processing elements may be involved: CRS and PDCCH processing:RxFFT, Channel Estimation (Ch Est), tracking loops (AGC/TTL/FTL), aswell as PDCCH demodulating and decoding. However, if CRS and PDCCHprocessing is made self-contained in a power-optimized subsystem, thepotential power saving would be greater. With respect to UE powerconsumption being affected by PWU duration, it should be appreciatedthat a PWU duration configured as short as possible and/or narrowbandprovides for efficiency. Based on a 5G self-contained subframestructure, 1˜2 subframes (0.5˜1 ms) is sufficient for a PWU durationaccording to some embodiments herein. In regard to UE power consumptionbeing affected by search space, the search space of embodiments may beconfigured to be limited to as few as possible for efficiency.Embodiments provide special radio network temporary identifiers (RNTIs)for scrambling (e.g., similar to paging). With respect to UE powerconsumption being affected by the duration of the gap between a PWUduration and corresponding ON duration (e.g., the magnitude of N in thegap of FIG. 3), if the gap is too long, sleep current may wipe out thegain. Assuming only light sleep, deep light sleep (DLS) may be performedbecause the duration of the gap (e.g., N) is likely below tens of ms andoffline processing needs to take place. Accordingly, the duration of thegap between a PWU duration and corresponding ON duration may be on theorder of few ms according to embodiments. Regarding UE power consumptionbeing affected by the percentage of WU-DRX cycles in which no data istransmitted to the UE, the UE can return to deep sleep after a PWUduration in which no control signal is detected, which leads to powersaving. Accordingly, generally the higher the percentage of WU-DRXcycles in which no data is transmitted to the UE, the lower the powerconsumption.

FIG. 4 shows an exemplary flow diagram illustrating operation of anembodiment of a multi-stage WU-DRX process, including a PWU stage and aWU stage as described above, as flow 400. Flow 400 may, for example, beperformed by logic and a receiver (e.g., controller/processor 258 andreceive processor 258 of FIG. 2) of a UE (e.g., any of UEs 115 of FIGS.1 and 2).

In operation of the WU-DRX multi-stage process provided by theillustrated embodiment of flow 400, the PWU stage provides a PWUduration for control signal monitoring prior to operation of one or morereceivers in a communication ready state (e.g., before an ON duration ofa C-DRX mode wherein a connection between the UE and eNB is provided inwhich the UE is configured to receive and transmit). Accordingly, atblock 401 of flow 400 the UE performs PWU stage processing to detect oneor more WU-DRX control signals (e.g., full WU signal, trigger signal,etc.). For example, one or more control signals (e.g., control signal310 of FIG. 3) may be provided to the UE during a PWU duration of a PWUstage. Accordingly, the UR may utilize a receiver configured for lowpower operation (e.g., a low power receive mode of a receiver of receiveprocessor 258, a WUR receiver of receiver processor 258 configured toperform non-coherent signal reception, etc.) to monitor for the one ormore control signals during the PWU duration.

At block 402 of the embodiment of flow 400 illustrated in FIG. 4, thePWU stage processing determines if one or more receivers (e.g., a mainor conventional receiver of receiver processor 258) of the UE are to betransitioned to a communication ready state. For example, a one or morecontrol signals (e.g., a full WU signal) may be provided to the UE in aPWU duration if data is to be expected during the ON duration and theone or more control signals may be detected by the UE at block 401.Logic (e.g., controller/processor 280) of the UE may analyze theoperation of the MU stage processing (e.g., determine if one or moreWU-DRX control signals are detected, analyze information provided byand/or with detected WU-DRX control signals, etc.) to determine if oneor more receivers of the UE are to be transitioned to a communicationready operation.

When it is determined that the one or more receivers are to betransitioned to communication ready operation, operation according tothe embodiment of flow 400 illustrated in FIG. 4 proceeds to block 403to perform WU stage processing of the WU-DRX process. In operation of WUstage processing according to the illustrated embodiment, the UEtransitions the one or more receivers from low power operation toconnection ready operation (e.g., controller/processor 280 may control atraditional or main receiver of receive processor 258 to exit a sleepstate). Thereafter, the UE may operate to receive and transmit dataduring an ON duration of a C-DRX mode, for example.

When it is determined that the one or more receivers are not to betransitioned to communication ready operation, operation according tothe embodiment of flow 400 illustrated in FIG. 4 proceeds to block 404to end the illustrated cycle of the WU-DRX process. In operation of theillustrated embodiment, if it is determined that the one or morereceivers are not to be transitioned to the communication readyoperation during the PWU stage processing, the cycle of the WU-DRXprocess is ended without performing WU stage processing. Thereafter, theUE may return to sleep (e.g., full sleep or deep sleep) after the PWUstage processing.

It should be appreciated that flow 400 of FIG. 4 illustrates operationof a single cycle of the exemplary WU-DRX process. Multiple WU-DRXcycles may be implemented (e.g., flow 400 repeated), such as inassociation with one or more events (e.g., in response to a trigger,anchored on start of control duration, etc.), according to apredetermined schedule, etc. Additionally or alternatively, WU-DRXcycles may be implemented in association with other processes, such asin a Full DRX cycle as described below with respect to FIG. 8.

FIG. 5 shows exemplary power profiles for a UE receiver operating inaccordance with a WU-DRX process using a WU control signal included onan ICH (or PDCCH) of embodiments. In particular, graph 510 shows anexemplary power profile for a WU-DRX cycle in which no downlink grant isprovided (e.g., WU-DRX cycle 301 a of FIG. 3). Graph 520 shows anexemplary power profile for a WU-DRX cycle in which an instance of adownlink grant is provided (e.g., WU-DRX cycle 301 b of FIG. 3). In theexample of FIG. 5, the wake up indicator channel (WU-ICH) signals that agrant will be scheduled and UE should monitor for the ON duration. Itshould be appreciated that the illustrations in FIG. 5 are simplifiedand that a low power mode for PDCCH processing may be done offline(e.g., outside of the PWU duration) and span more than 1 subframe,wherein an offset (e.g., the gap between a PWU duration andcorresponding ON duration described above) may be defined between thePWU duration and a corresponding ON duration.

FIG. 6 shows exemplary power profiles for a UE receiver operating inaccordance with a WU-DRX process using a WUR of embodiments. Inparticular, graph 610 shows an exemplary power profile for a WU-DRXcycle in which no downlink grant is provided (e.g., WU-DRX cycle 301 aof FIG. 3). Graph 620 shows an exemplary power profile for a WU-DRXcycle in which an instance of a downlink grant is provided (e.g., WU-DRXcycle 301 b of FIG. 3). It can be appreciated from the graphs of FIG. 6that an inactivity timer (e.g., an inactivity timer utilized in the ONduration to determine when the UE receiver transitions from the ONduration and returns to sleep) may be shortened in an implementationutilizing a WUR of embodiments because it is as power efficient toconfigure a shorter WU-DRX cycle, while still achieving the same orlower latency. As a further enhancement, instead of relying oninactivity timer, the eNB of embodiments may issue a special DRX commandto put UE to sleep.

FIG. 7 shows exemplary power profiles for a UE receiver operating inaccordance with a LTE C-DRX process for comparison to the power profilesprovided by embodiments of a WU-DRX process herein. In particular, graph710 shows an exemplary power profile for a C-DRX cycle in which nodownlink grant is provided. Graph 720 shows an exemplary power profilefor a C-DRX cycle in which an instance of a downlink grant is provided.As can be seen by comparison to the corresponding graphs of FIGS. 5 and6, both the WU control signal and WUR implementations of the exemplaryWU-DRX process embodiments provide substantial power savings over theLTE C-DRX process.

Various robust WU-DRX configurations may be provided according toembodiments of the present disclosure. Robust WU-DRX configurations may,for example, be configured to provide low power operation duringintervals of inactivity in an ON duration, to provide support forperiodic radio/network updates and/or to provide an alternativetechnique for transitioning to instances of ON durations, etc.

In an example of a robust WU-DRX configuration in which low poweroperation is provided during intervals of inactivity in an ON duration,one or more receivers of the UE may be controlled to refrain fromdownlink monitoring (e.g., entering a sleep mode) during inactivityintervals within. ON durations. Operation to provide low power operationduring inactivity intervals as may be implemented by a WU-DRXconfiguration in accordance with the concepts herein is shown anddescribed in U.S. patent application Ser. No. 15/188,720, entitled“MACRO AND MICRO DISCONTINUOUS RECEPTION,” the disclosure of which isincorporated herein by reference.

If a PWU stage is performed using a low-power WUR, the WUR may not becapable of performing some of the “maintenance” type operations, aspreviously mentioned. Additionally, if the WU-DRX cycle is very short(e.g., <40 ms), periodic radio/network updates may not need to beperformed during every WU-DRX cycle (e.g., a short DRX cycle may bedriven by low latency requirement, decoupled from high mobilityrequirements), regardless of whether a WUR is used or not. Accordingly,a robust WU-DRX configuration operable to support periodic radio/networkupdates and/or to provide an alternative technique for transitioning toinstance of ON durations implements Full DRX cycles (e.g., DRX cycles inwhich the full UE modem wakes up) in combination with the WU-DRX cyclesof a WU-DRX process. The Full DRX cycle of embodiments provides forced(e.g., periodic) DRX cycle operation (e.g., C-DRX cycles) providinginstances of an ON duration to supplement the WU-DRX cycles. However,the instances of ON durations for the WU-DRX cycles remain conditionalon WU control signals detected in the PWU duration. The implementationof Full DRX cycles according to embodiments may provide a fall-back DRXscheme (e.g., the full UE modem wakes up to monitor ON duration with aperiodicity not larger than a full DRX cycle) in case WU-DRX fails(e.g., in a situation where the PWU stage chronically suffers misseddetection) and/or for periodic network “maintenance” (e.g.RLM/RRM/periodic CSI), thereby enhancing the robustness of the WU-DRXprocess.

FIG. 8 shows an exemplary implementation of a Full DRX cycle incombination with the WU-DRX cycles of a WU-DRX process herein. The FullDRX cycle of FIG. 8 spans multiple WU-DRX cycles. For example, the FullDRX cycle is equal to N*(WU-DRX cycle), wherein N=4 in the illustratedexample. In the illustrated example, the ON duration is set to 2subframes.

In operation according to embodiments, RLM/CSF/RRM/Sync periodicity maybe aligned to the Full DRX cycle. For example, the WU-DRX cycle may be20 ms, but the periodic RLM/CSF/RRM operations may be performed every320 ms in correspondence with the Full DRX cycle. It is also possiblefor each operation (RLM or CSF or RRM or Sync) to be aligned todifferent multiples of the full DRX cycle, according to embodiments. Forexample, RLM may be done every full DRX cycle, and RRM may be done everytwo full DRX cycles, adapting to the requirement for each operation. Inembodiments utilizing a WUR for the PWU stage of a WU-DRX cycle, themain UE modem may be controlled to wake up regardless of detection of acontrol signal in the PWU duration in order to perform channel-dependentoperations. Embodiments may operate to provide on-demand RLM/CSF/RRMtriggered by a control signal in the PWU duration.

Periodic CSI may be aligned to the longer cycle of the Full DRX cycle(e.g., multiple of WU-DRX cycles). In embodiments, a CSI referencesignal (CSI-RS) may be transmitted by the eNB and received by the UE forperiod CSI measurement and reporting. Such a CSI-RS may be used forradio link monitoring (RLM) according to embodiments.

In operation according to embodiments, enhancements to RLM, Sync, andRRM operations may be provided by allowing a faster cadence than theFull DRX cycle. A control signal detected in the PWU duration may alsobe conditionally utilized to assist radio link monitoring (RLM)operation. For example, if the level of a WU control signal detected inthe PWU duration is strong, it can be used to infer a good radio linkcondition. If a synchronization signal is available and suited forprocessing by the receiver employed for the PWU duration,synchronization operation may also be performed during the PWU durationof a WU-DRX cycle. If such synchronization signal from the serving andneighbor cells can be detected, some of the radio resource management(RRM) functionalities can be performed during the PWU duration of aWU-DRX cycle.

In instances where a WU-DRX cycle is aligned to a Full DRX cycle, thePWU duration of the WU-DRX cycle may be made optional since the wake upoperation has to occur. Embodiments, however, may nevertheless continueto utilize the PWU duration of WU-DRX cycles that are aligned to FullDRX cycles, such as where the control signals detected during a PWUduration carry additional information other than wake-up indication.

FIG. 9 shows an exemplary implementation of a Full DRX cycle incombination with the WU-DRX cycles of a WU-DRX process wherein the FullDRX cycle is flexible. Similar to the embodiment illustrated in FIG. 8,the embodiment of FIG. 9 provides a Full DRX cycle that is a multiple ofthe WU-DRX cycle. However, instead of forcing the WU-DRX cycle which isaligned to the Full DRX cycle to have active ON duration (i.e. forcedwake-up), a window in terms of a number of WU-DRX cycles is defined.This window in the illustrated embodiment is aligned to the end of theFull DRX cycle. Accordingly, if any of an ON duration of a WU-DRX cycleis active (e.g., having been triggered by WU control signal) within thewindow, the robustness condition is satisfied. In a first scenarioillustrated in FIG. 9, a PWU stage triggered wake up occurs on the firstsubframe in the window and the full UE modem is not forced to wake-upagain for the remainder of the window. In a second scenario illustratedin FIG. 9, at the final PWU duration within the window, no wake up hasbeen triggered by the WU-DRX cycle and a wake up is forced for the lastON duration before the window ends. A benefit of this flexible scheme ishigher timing flexibility for RLM/CSF/RRM/Sync operations, generallyresulting in reduced full wake up. Periodic radio/network updateactivities may additionally or alternatively be anchored to any one ofthe active ON duration within the window.

It should be appreciated that, although embodiments herein have beendiscussed with reference to a multi-stage WU-DRX process in which a PWUstage is implemented to determine whether to initiate an ON duration ofC-DRX mode operation, WU-DRX processes may be utilized with respect tovarious other operations. For example, a PWU stage may be implemented todetermine whether to initiate an ON duration of I-DRX mode operationaccording to concepts herein.

Those of skill in the art would understand that information and signalsmay be represented using any of a variety of different technologies andtechniques. For example, data, instructions, commands, information,signals, bits, symbols, and chips that may be referenced throughout theabove description may be represented by voltages, currents,electromagnetic waves, magnetic fields or particles, optical fields orparticles, or any combination thereof.

The functional blocks and modules in FIG. 2 may comprise processors,electronics devices, hardware devices, electronics components, logicalcircuits, memories, software codes, firmware codes, etc., or anycombination thereof. The operations described with respect to performingWU-DRX process functionality described with reference to FIGS. 3-6, 8,and 9 may be performed by the functional blocks of FIG. 2, such as byoperation of processors, electronics devices, hardware devices,electronics components, logical circuits, memories, software codes,and/or firmware codes thereof.

Those of skill would further appreciate that the various illustrativelogical blocks, modules, circuits, and algorithm steps described inconnection with the disclosure herein may be implemented as electronichardware, computer software, or combinations of both. To clearlyillustrate this interchangeability of hardware and software, variousillustrative components, blocks, modules, circuits, and steps have beendescribed above generally in terms of their functionality. Whether suchfunctionality is implemented as hardware or software depends upon theparticular application and design constraints imposed on the overallsystem. Skilled artisans may implement the described functionality invarying ways for each particular application, but such implementationdecisions should not be interpreted as causing a departure from thescope of the present disclosure. Skilled artisans will also readilyrecognize that the order or combination of components, methods, orinteractions that are described herein are merely examples and that thecomponents, methods, or interactions of the various aspects of thepresent disclosure may be combined or performed in ways other than thoseillustrated and described herein.

The various illustrative logical blocks, modules, and circuits describedin connection with the disclosure herein may be implemented or performedwith a general-purpose processor, a digital signal processor (DSP), anapplication specific integrated circuit (ASIC), a field programmablegate array (FPGA) or other programmable logic device, discrete gate ortransistor logic, discrete hardware components, or any combinationthereof designed to perform the functions described herein. Ageneral-purpose processor may be a microprocessor, but in thealternative, the processor may be any conventional processor,controller, microcontroller, or state machine. A processor may also beimplemented as a combination of computing devices, e.g., a combinationof a DSP and a microprocessor, a plurality of microprocessors, one ormore microprocessors in conjunction with a DSP core, or any other suchconfiguration.

The steps of a method or algorithm described in connection with thedisclosure herein may be embodied directly in hardware, in a softwaremodule executed by a processor, or in a combination of the two. Asoftware module may reside in RAM memory, flash memory, ROM memory,EPROM memory, EEPROM memory, registers, hard disk, a removable disk, aCD-ROM, or any other form of storage medium known in the art. Anexemplary storage medium is coupled to the processor such that theprocessor can read information from, and write information to, thestorage medium. In the alternative, the storage medium may be integralto the processor. The processor and the storage medium may reside in anASIC. The ASIC may reside in a user terminal. In the alternative, theprocessor and the storage medium may reside as discrete components in auser terminal.

In one or more exemplary designs, the functions described may beimplemented in hardware, software, firmware, or any combination thereof.If implemented in software, the functions may be stored on ortransmitted over as one or more instructions or code on acomputer-readable medium. Computer-readable media includes both computerstorage media and communication media including any medium thatfacilitates transfer of a computer program from one place to another.Computer-readable storage media may be any available media that can beaccessed by a general purpose or special purpose computer. By way ofexample, and not limitation, such computer-readable media can compriseRAM, ROM, EEPROM, CD-ROM or other optical disk storage, magnetic diskstorage or other magnetic storage devices, or any other medium that canbe used to carry or store desired program code means in the form ofinstructions or data structures and that can be accessed by ageneral-purpose or special-purpose computer, or a general-purpose orspecial-purpose processor. Also, a connection may be properly termed acomputer-readable medium. For example, if the software is transmittedfrom a website, server, or other remote source using a coaxial cable,fiber optic cable, twisted pair, or digital subscriber line (DSL), thenthe coaxial cable, fiber optic cable, twisted pair, or DSL, are includedin the definition of medium. Disk and disc, as used herein, includescompact disc (CD), laser disc, optical disc, digital versatile disc(DVD), floppy disk and blu-ray disc where disks usually reproduce datamagnetically, while discs reproduce data optically with lasers.Combinations of the above should also be included within the scope ofcomputer readable media.

As used herein, including in the claims, the term “and/or,” when used ina list of two or more items, means that any one of the listed items canbe employed by itself, or any combination of two or more of the listeditems can be employed. For example, if a composition is described ascontaining components A, B, and/or C, the composition can contain Aalone; B alone; C alone; A and B in combination; A and C in combination;B and C in combination; or A, B, and C in combination. Also, as usedherein, including in the claims, “or” as used in a list of itemsprefaced by “at least one of” indicates a disjunctive list such that,for example, a list of “at least one of A, B, or C” means A or B or C orAB or AC or BC or ABC (i.e., A and B and C) or any of these in anycombination thereof.

The previous description of the disclosure is provided to enable anyperson skilled in the art to make or use the disclosure. Variousmodifications to the disclosure will be readily apparent to thoseskilled in the art, and the generic principles defined herein may beapplied to other variations without departing from the spirit or scopeof the disclosure. Thus, the disclosure is not intended to be limited tothe examples and designs described herein but is to be accorded thewidest scope consistent with the principles and novel features disclosedherein.

What is claimed is:
 1. A method for providing power-conserving operationof user equipment (UE) in a cellular communication network, the methodcomprising: monitoring, by a UE, in a reduced power mode, for differentsignals during a pre-wake up (PWU) stage of a multiple stage wake up(WU) process, the WU process comprising low power processing of one ormore signals received by the UE in the PWU stage, the different signalsconfigured to either: (a) transition one or more receivers of the UEfrom low power operation to operation configured to receive and transmitdata during an ON duration of a WU stage of the multiple stage WUprocess; or (b) end a cycle of the multiple stage WU process withoutperforming the WU stage of the multiple stage WU process, wherein one ofthe different signals is configured to indicate that data for the UE isexpected during the ON duration of the WU stage following the PWU stage,wherein a power level associated with the reduced power mode isintermediate to power level associated with UE operation during the lowpower operation and power level associated with UE operation during theON duration of the WU stage, and wherein the power level associated withUE operation during ON duration of the WU stage is greater than thepower level associated with UE operation during the low power operation;and transitioning the one or more receivers of the UE from the low poweroperation to the operation configured to receive and transmit dataduring the ON duration of the WU stage of the multiple stage WU processwhen it is determined that the one or more receivers are to betransitioned to the operation configured to receive and transmit dataduring the ON duration based on the monitoring for the one of thedifferent signals in the PWU stage detecting the one of the differentsignals; or ending a current cycle of the multiple stage WU processwithout performing the WU stage when it is determined that the one ormore receivers are not to be transitioned to the operation configured toreceive and transmit data during the ON duration based on the monitoringfor the one of the different signals in the PWU stage failing to detectthe one of the different signals.
 2. The method of claim 1, wherein atleast one receiver of the one or more receivers of the UE operates inthe reduced power mode during the PWU stage to monitor for the differentsignals.
 3. The method of claim 1, wherein a wake up receiver that isnot a receiver of the one or more receivers of the UE operates duringthe PWU stage to monitor for the different signals.
 4. The method ofclaim 1, wherein the monitoring for the different signals comprises:using non-coherent signal detection by a receiver of the UE.
 5. Themethod of claim 4, wherein using non-coherent signal detection includesmonitoring for the control signal without estimating a channel relatedto the control signal during the PWU stage.
 6. The method of claim 1,wherein the UE operates to perform wake up processing during the WUstage to transition the one or more receivers of the UE from low poweroperation to the operation configured to receive and transmit dataduring the ON duration.
 7. The method of claim 6, wherein the wake upprocessing comprises the low power processing of the one or more signalsreceived by the UE in the PWU stage.
 8. The method of claim 6, whereinthe wake up processing comprises make-ready of the one or more receiversof the UE.
 9. The method of claim 1, wherein the different signals aremultiplexed with one or more one or more data channels for at least oneother UE operable in the cellular communication network, and wherein thelow power processing comprises: performing low power receiver processingof the multiplexed signals in the PWU stage.
 10. The method of claim 9,wherein the different signals multiplexed with the one or more datachannels for the at least one other UE comprises an on-off keying (OOK)signal within orthogonal frequency division multiplexed (OFDM) signals.11. The method of claim 1, wherein the different signals comprisesinformation selected from the group consisting of control channelassignment data, data channel subband assignment, and bandwidthinformation that indicates whether additional data is expected to betransmitted to the UE.
 12. The method of claim 1, further comprising:performing a plurality of cycles of the multiple stage WU process in afull discontinuous reception (Full DRX) cycle, wherein the Full DRXcycle includes the plurality of cycles of the multiple stage WU processand at least one cycle forcing the one or more receivers of the UE totransition to the operation configured to receive and transmit dataduring the ON duration independent of the monitoring for the differentsignals in the PWU stage.
 13. The method of claim 12, wherein aperiodicity of the Full DRX cycle is configured to remediate a situationwhere the PWU stage of the WU process cycles chronically suffers misseddetection of the different signals.
 14. The method of claim 12, whereina periodicity of the Full DRX cycle is configured to facilitate periodicnetwork maintenance communications.
 15. The method of claim 1, whereinanother one of the different signals is configured to trigger atransmission response from the one or more receivers.
 16. The method ofclaim 15, wherein the another one of the different signals is configuredto trigger an aperiodic channel state information report procedure. 17.The method of claim 15, wherein the another one of the different signalsis configured to trigger transmission of a sounding reference signal.18. An article of manufacture comprising: a non-transitorycomputer-readable medium having stored therein instructions forproviding power-conserving operation of user equipment (UE) in acellular communication network, wherein the instructions are executableby a processor of the UE to: monitor, in a reduced power mode, fordifferent signals during low power operation of a pre-wake up (PWU)stage of a multiple stage wake up (WU) process, the WU processcomprising low power processing of one or more signals received by theUE in the PWU stage, the different signals configured to eithertransition one or more receivers of a UE from low power operation tooperation configured to receive and transmit data during an ON durationof a WU stage of the multiple stage WU process or end a cycle of themultiple stage WU process without performing the WU stage of themultiple stage WU process, wherein one of the different signals isconfigured to indicate that data for the UE is expected during the ONduration of the WU stage following the PWU stage, wherein a power levelassociated with the reduced power mode is intermediate to power levelassociated with UE operation during the low power operation and powerlevel associated with UE operation during the ON duration of the WUstage; transition the one or more receivers of the UE from the low poweroperation to the operation configured to receive and transmit dataduring the ON duration of the WU stage of the multiple stage WU processwhen it is determined that the one or more receivers are to betransitioned to the operation configured to receive and transmit dataduring the ON duration based on the monitoring for the one of thedifferent signals in the PWU stage detecting the one of the differentsignals; and end a current cycle of the multiple stage WU processwithout performing the WU stage when it is determined that the one ormore receivers are not to be transitioned to the operation configured toreceive and transmit data during the ON duration based on the monitoringfor the one of the different signals in the PWU stage failing to detectthe one of the different signals.
 19. The article of manufacture ofclaim 18, wherein at least one receiver of the one or more receivers ofthe UE operates in the reduced power mode during the PWU stage tomonitor for the different signals.
 20. The article of manufacture ofclaim 18, wherein a wake up receiver that is not a receiver of the oneor more receivers of the UE operates during the PWU stage to monitor fordifferent signals.
 21. The article of manufacture of claim 18, whereinthe instructions to monitor for the different signals comprisesinstructions to: use non-coherent signal detection by a receiver of theUE.
 22. The article of manufacture of claim 18, wherein the UE operatesto perform wake up processing during the WU stage to transition the oneor more receivers of the UE from low power operation to the operationconfigured to receive and transmit data during the ON duration.
 23. Thearticle of manufacture of claim 22, wherein the wake up processingcomprises the low power processing of the one or more signals receivedby the UE in the PWU stage.
 24. The article of manufacture of claim 22,wherein the wake up processing comprises make-ready of the one or morereceivers of the UE.
 25. The article of manufacture of claim 18, whereinthe different signals are multiplexed with one or more one or more datachannels for at least one other UE operable in the cellularcommunication network, and wherein instructions executable by theprocessor to perform the low power processing of one or more signalsreceived by the UE in the PWU stage comprise instructions to: performlow power receiver processing of the multiplexed signals in the PWUstage.
 26. The article of manufacture of claim 25, wherein the differentsignals multiplexed with the one or more data channels for the at leastone other UE comprises an on-off keying (OOK) signal within orthogonalfrequency division multiplexed (OFDM) signals.
 27. The article ofmanufacture of claim 18, wherein the different signals comprisesinformation selected from the group consisting of control channelassignment data, data channel subband assignment, and bandwidthinformation that indicates whether additional data is expected to betransmitted to the UE.
 28. The article of manufacture of claim 18,wherein the instructions further comprises instructions to: perform aplurality of cycles of the multiple stage WU process in a fulldiscontinuous reception (Full DRX) cycle, wherein the Full DRX cycleincludes the plurality of cycles of the multiple stage WU process and atleast one cycle forcing the one or more receivers of the UE totransition to the operation configured to receive and transmit dataduring the ON duration independent of the monitoring for differentsignals in the PWU stage.
 29. The article of manufacture of claim 28,wherein a periodicity of the Full DRX cycle is configured to remediate asituation where the PWU stage of the WU process cycles chronicallysuffers missed detection of the different signals.
 30. The article ofmanufacture of claim 28, wherein a periodicity of the Full DRX cycle isconfigured to facilitate periodic network maintenance communications.31. An apparatus for providing power-conserving operation of userequipment (UE) in a cellular communication network, the apparatuscomprising: at least one processor; and a memory coupled to the at leastone processor, wherein the at least one processor is configured: tomonitor, in a reduced power mode, for different signals during low poweroperation of a pre-wake up (PWU) stage of a multiple stage wake up (WU)process, the WU process comprising low power processing of one or moresignals received by the UE in the PWU stage, the different signalsconfigured to either transition one or more receivers of a UE from lowpower operation to operation configured to receive and transmit dataduring the ON duration of a WU stage of the multiple stage WU process orend a cycle of the multiple stage WU process without performing the WUstage of the multiple stage WU process, wherein one of the differentsignals is configured to indicate that data for the UE is expectedduring the ON duration of the WU stage following the PWU stage, whereina power level associated with the reduced power mode is intermediate topower level associated with UE operation during the low power operationand power level associated with UE operation during the ON duration ofthe WU stage; to transition the one or more receivers of the UE from thelow power operation to the operation configured to receive and transmitdata during the ON duration of the WU stage of the multiple stage WUprocess when it is determined that the one or more receivers are to betransitioned to the operation configured to receive and transmit dataduring the ON duration based on the monitoring for the one of thedifferent signals in the PWU stage detecting the one of the differentsignals; and to end a current cycle of the multiple stage WU processwithout performing the WU stage when it is determined that the one ormore receivers are not to be transitioned to the operation configured toreceive and transmit data during the ON duration based on the monitoringfor the one of the different signals in the PWU stage failing to detectthe one of the different signals.
 32. The apparatus of claim 31, whereinat least one receiver of the one or more receivers of the UE operates inthe reduced power mode during the PWU stage to monitor for the differentsignals.
 33. The apparatus of claim 31, wherein a wake up receiver thatis not a receiver of the one or more receivers of the UE operates duringthe PWU stage to monitor for the different signals.
 34. The apparatus ofclaim 31, wherein the at least one processor configured to monitor forthe different signals is further configured: to use non-coherent signaldetection by a receiver of the UE.
 35. The apparatus of claim 31,wherein the UE operates to perform wake up processing during the WUstage to transition the one or more receivers of the UE from low poweroperation to the operation configured to receive and transmit dataduring the ON duration.
 36. The apparatus of claim 35, wherein the wakeup processing comprises the low power processing of the one or moresignals received by the UE in the PWU stage.
 37. The apparatus of claim35, wherein the wake up processing comprises make-ready of the one ormore receivers of the UE.
 38. The apparatus of claim 31, wherein thedifferent signals are multiplexed with one or more one or more datachannels for at least one other UE operable in the cellularcommunication network, the at least one processor configured to performthe low power processing of one or more signals received by the UE inthe PWU stage is further configured: to perform low power receiverprocessing of the multiplexed signals in the PWU stage.
 39. Theapparatus of claim 38, wherein the different signals multiplexed withthe one or more data channels for the at least one other UE comprises anon-off keying (OOK) signal within orthogonal frequency divisionmultiplexed (OFDM) signals.
 40. The apparatus of claim 31, wherein thedifferent signals comprises information selected from the groupconsisting of control channel assignment data, data channel subbandassignment, and bandwidth information that indicates whether additionaldata is expected to be transmitted to the UE.
 41. The apparatus of claim31, the at least one processor further configured: to perform aplurality of cycles of the multiple stage WU process in a fulldiscontinuous reception (Full DRX) cycle, wherein the Full DRX cycleincludes the plurality of cycles of the multiple stage WU process and atleast one cycle forcing the one or more receivers of the UE totransition to the operation configured to receive and transmit dataduring the ON duration independent of the monitoring for the differentsignals in the PWU stage.
 42. The apparatus of claim 41, wherein aperiodicity of the Full DRX cycle is configured to remediate a situationwhere the PWU stage of the WU process cycles chronically suffers misseddetection of the different signals.
 43. The apparatus of claim 41,wherein a periodicity of the Full DRX cycle is configured to facilitateperiodic network maintenance communications.